Our overall goal is to understand the behavioral and neural relationships between affect and language, two expressive human systems which provide a means to communicate our thoughts, beliefs, and desires. We address these issues by investigating linguistic and emotional development in special populations, each of which offers an opportunity to explore some facet of the components, boundaries, or underlying neural substrates of these systems. The populations include: infants and children with early focal unilateral brain damage, infants of substance abusing mothers; deaf children of deaf parents who are acquiring American Sign Language as their first language; children with Williams syndrome; children with Down syndrome and normal hearing children. Projects investigate the development of emotional expression, emotional representation, or knowledge of emotion as well as the linguistic and non-linguistic expression of emotion in these children. By chronicling the development of language and emotional expression in these children as well as their intersections, we will better understand their underlying cognitive organization. These data will also be instrumental in developing an intervention program for these infants and their caregivers. As in the past, MBRS students will be involved in all phases of the research.